What two planets in our solar system have no moons?

More Questions:

What were barcodes first used for?

Which chess piece can only move diagonally?

In a symphony orchestra, what instrument is played by the concertmaster?

American mass murderer Ronald DeFeo Jr. was the inspiration behind what novel and series of films?

What author created Earthsea?

Who wrote the poem "Anthem for Doomed Youth"?

What is measured in fathoms?

What are the six most abundant Greenhouse Gases?

What color is a polar bear's skin?

What constellation's Latin name translates as "Smaller Bear" or "Little Bear"?

Who said the famous line "Here's looking at you, kid"?

Whose directorial debut earned him an Oscar for Ordinary People in 1980?

The Maginot line was a defensive system constructed to protect what?

What Undersecretary of the United Nations became the first African-American to win the Nobel Peace Prize?

What Spanish explorer conquered Montezuma and the Aztecs?